Digesta dynamics, nutrition messaging and (ultra)processed food

Abstract

There are two disparate approaches used to communicate nutritional attributes of foods, based on nutrient composition and food type. Nutrient content fails to account for the rate and site of nutrient absorption, and food type does not differentiate between diverse forms of the same type. The scope of this review is to examine whether a combination of nutrient composition and digesta dynamics provides a coherent framework for rationalising health benefits associated with whole foods, and explaining dietary risk factors associated with chronic non-communicable diseases. Digesta dynamics encompasses the timescales and rates of mouth, stomach, small intestine and large intestine processing. Key concepts include chewing extent, gastric transit time, small intestinal digestion/absorption rate, the proportion of digestate that escapes digestion by the end of the small intestine, and large intestine fermentation rate and extent. Food processing can have profound consequences on digesta dynamics, often resulting in shorter gastric transit, faster small intestinal digestion, less undigested food at the end of the small intestine, and rapid large intestine fermentation. If processing effects act through changes in digesta dynamics, there is no reason to differentiate between factory-processed and analogous kitchen-processed foods. Nutrition messaging based on digesta dynamics as well as nutrient composition would avoid the scapegoating of additives that have no connection to risk factors for common chronic non-communicable conditions. Ultraprocessed foods should be seen as a “brand” that creates an emotional connection with consumers as part of general nutrition messaging, rather than a technical categorisation that distinguishes ‘healthy’ and ‘unhealthy’ foods.